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Talazoparib Beyond BRCA (TBB) Trial

Talazoparib Beyond BRCA (TBB) Trial

Clinicaltrials.gov identifier:


Study Contact Information:

The study is being conducted by researchers at Stanford University Hospital. Contact Pei Jen Chang by phone at 310-967-4339 or by email.   


Talazoparib Beyond BRCA (TBB) Trial

About the Study

The goal of the study is to evaluate the anti-cancer activity of Talazoparib (a type of treatment known as a PARP inhibitor) in patients with advanced breast cancer with specific genetic mutations based on a blood, saliva, or tumor test. See the clinicaltrials.gov listing for additional information.

The study is open to people with advanced breast cancer. There are two cohorts both of which will receive the same treatment.  

  • Cohort A
    • triple negative breast cancer and a tumor test that shows homologous recombination deficiency (HRD) based on the Myriad HRD Assay, or
  • Cohort B
    • an inherited mutation or a mutation in their tumor in one of the following genes:
      • PTEN
      • PALB2
      • CHEK2
      • ATM
      • NBN
      • BARD1
      • BRIP1
      • RAD50
      • RAD51C
      • RAD51D
      • MRE11
      • ATR
      • Fanconi anemia complementation group of genes (FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL)

This study is not open to people with a BRCA1 or BRCA2 mutation. 

Type of Study

This is an open-label, single-arm study.

  • The study has one arm. This means that all patients in the study will receive the same treatment, talazoparib

What the Study Entails

  • Patients receive Talazoparib 1 mg by mouth daily.

Study Lead Investigator

Melinda Telli, MD: Stanford University Hospital

This Study is Open To:

Patients with advanced breast cancer who:

  • do not have an inherited BRCA1 or BRCA2 mutation based on full sequencing and comprehensive rearrangement testing at an external reference laboratory (Myriad Genetics); patients with variants of unknown significance will be eligible
  • have measurable disease 
  • have progressed on at least 1 chemotherapy regimen for treatment of advanced breast cancer; there is no upper limit on the number of prior therapies


  • metastatic triple-negative breast cancer and an HRD score >= 42 on the Myriad HRD Assay as assessed on a tumor biopsy sample.
    • note: in the case that obtaining an adequate metastatic tumor biopsy is not possible, we will assess the HRD score from the primary breast tumor


  • histologically confirmed metastatic HER2-negative breast cancer
  • deleterious germline (inherited) or somatic (tumor) mutation implicated in the homologous recombination (HR) pathway, (excluding BRCA1 or BRCA2), based on germline multiplex gene testing or direct tumor next generation DNA sequencing. Genes of interest include:
    • PTEN, PALB2, CHEK2, ATM, NBN, BARD1, BRIP1, RAD50, Rad51c, Rad51d, MRE11, ATR, FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL, plus other HR-related genes at the discretion of the primary investigators.
This Study is Not Open To:
  • Any patient with a deleterious mutation in BRCA1 or BRCA2
  • Prior treatment with a platinum agent (i.e. cisplatin or carboplatin)
  • Prior treatment with a PARP inhibitor
  • Non-measurable disease only
  • Pregnant or nursing patients
  • Any anti-cancer therapy within the past 21 days of the first day of treatment
  • Brain or central nervous system (CNS) metastases that are progressive or symptomatic, have not been previously resected or irradiated, or are the only site of measurable disease
  • Other malignancy that is either active or for which patient has received treatment in the last five years excluding non-melanoma skin cancer and carcinoma in situ of the cervix
  • Use of any investigational product (IP) or investigational medical device within 28 days before day 1 of study drug
  • Major surgery requiring a prolonged hospitalization or recovery within 21 days before day 1 of study drug